MORPHOLOGICAL UNITY OF LIVING BEINGS. 169 



support or basis of cellular life, are groups of micella 

 formed of albuminoid substances and water. These 

 clustered forms, these micellae, are not absolutely 

 peculiar to organized matter. PfefFer, the learned 

 botanist, has pointed them out under another name, 

 tagmata, in the membranes of chemical precipitates. 



Beyond this limit analysis finds nothing but the 

 chemical molecule and the atom. So that if we 

 wish to reconstruct the hierarchy of the materials of 

 constitution of the protoplasm in order of ascending 

 complexity, xve shall find at the foundation the atom or 

 atoms of simple bodies. They are principally carbon, 

 hydrogen, oxygen, nitrogen, the elements of all 

 organic compounds, to which may be added sulphur 

 and phosphorus. At the head we have the albu- 

 minoid molecule, or the albuminoid molecules, 

 aggregates of the preceding atoms. In the third 

 stage the micellae or tagmata, aggregates of albu- 

 minoids and water, are still too small to be observed 

 by the senses. They unite in their turn to form the 

 microsomes, the first elements visible to the micro- 

 scope. The microsomes, cemented by linin, form the 

 filaments or links which are called mitomes. The 

 living protoplasm is therefore nothing but a chain, or 

 tangled skein, or a spongy skeleton formed by its 

 filaments. 



Such is the typical constitution of living matter 

 according to microscopic observation, supplemented by 

 a perfectly reasonable hypothesis, which is, so to speak, 

 only a translation of one of its most evident physical 

 properties. This relatively simple scheme has become 

 a complex scheme in the hands of later biologists. 

 On the micellar hypothesis, which seems almost 

 inevitable in its character, new hypotheses have been 



